Technical Field
The present disclosure relates to a measurement apparatus and a measurement method with an adaptive scan rate, and more particularly, to a measurement apparatus and a measurement method capable of increasing a measurement speed by variably applying a scan rate by using data about an at least immediately previously measured fast scan line.
Description of the Related Art
A Scanning Probe Microscope (SPM) refers to a microscope configured to measure surface characteristics of a sample while scanning a probe manufactured by an MEMS process over a surface of the sample, and show the surface characteristics of the sample in a 3D image. The SPM can be subdivided into an Atomic Force Microscope (AFM), a Scanning Tunneling Microscope (STM), and the like depending on a measurement method.
FIG. 1 is a schematic perspective view of an atomic force microscope of the prior art in which an XY-scanner is separated from a Z-scanner.
Referring to FIG. 1, an atomic force microscope 10 includes a cantilever 2 configured to follow a surface of a measurement target 1 in a contact or non-contact state, an XY-scanner 11 configured to scan the measurement target on an XY-plane in an X direction and a Y-direction, a Z-scanner 21 connected with the cantilever 2 and configured to move the cantilever 2 in a Z-direction with a relatively small displacement, a Z-stage 12 configured to move the cantilever 2 and the Z-scanner 21 in the Z-direction with a relatively large displacement, and a frame 13 configured to fix the XY-scanner 11 and the Z-stage 12.
The atomic force microscope 10 obtains an image such as a topographic image by scanning a surface of the measurement target 1 with the cantilever 2. A relative movement between the surface of the measurement target 1 and the cantilever 2 can be carried out by the XY-scanner 11, and a vertical movement of the cantilever 2 along the surface of the measurement target 1 can be carried out by the Z-scanner 21. Meanwhile, the cantilever 2 is connected with the Z-scanner 21 through a probe arm 22.
A scanning probe microscope like the atomic force microscope 10 needs to physically scan the entire surface of the measurement target 1 with the cantilever 2. As a scan rate is increased, it is difficult for the Z-scanner 21 to maintain proper feedback. Thus, an image quality may deteriorate. In particular, if the surface of the measurement target 1 has a high step-height, it is difficult to obtain feedback of the cantilever. Thus, it is inevitable to lower the scan rate. That is, an image quality and a scan rate are not easily compatible with each other in the scanning probe microscope as a scanning-based apparatus. Accordingly, a low image throughput has been an obstacle to widen application of the scanning probe microscope in the industrial world.